What Equations Govern This Hypothetical Fluid Flow?

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In summary, the conversation discusses a hypothetical 2D inviscid, steady, uniform, and parallel potential flow, and the speaker's approach to solving for a velocity profile. They mention consulting the Navier-Stokes Equations and considering various factors such as steady flow, inviscid flow, parallel flow, potential flow, and uniform flow. They also ask for confirmation on their proposed equation of motion.
  • #1
member 428835
Hi PF!

I was reading lecture notes from a university and I stumbled on this situation:

We have a hypothetical 2D inviscid, steady, uniform and parallel, potential flow, described by
the velocity vector ## \vec{v} = <u,w>##, with ##u= U[z]## and ##w= W[z]##. It is moving parallel to a stationary plate that lies along the ##x## axis. By “parallel,” it is meant that flow is everywhere parallel to the plate.
By “uniform”, it is meant that the flow is spatially uniform. By “steady”, it is meant that the flow
is time invariant.

When solving for a velocity profile, my first thought was to consult the Navier-Stokes Equations for ractangular coordinates and go from there. What I was thinking was steady implies ##\partial_t = 0##, inviscid implies ##\mu = 0## (or would this be ##\nabla \times \vec{v} = 0##?). Parallel implies ##v_y = 0## where ##y## is orthogonal to the base plate (I think ##u## and ##w## move in the plate direction and from side-to-side respectively (any ideas here)? Potential implies the existence of some scalar ##\phi : \vec{v} = \nabla \phi##. Uniform implies ##\partial_x v = \partial_z v = 0##.

Can someone confirm this?

If I'm right, the equation of motion would simply be ##\nabla ^2 \vec{v} = 0 \implies \nabla^2 u = 0## and ##\nabla^2 w = 0##. Do you agree or disagree?
 
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  • #2
Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
 

Related to What Equations Govern This Hypothetical Fluid Flow?

1) What is the equation for calculating fluid flow?

The most commonly used equation for calculating fluid flow is the Navier-Stokes equation, which takes into account factors such as viscosity, pressure, and velocity.

2) How do I solve for fluid flow in a specific system?

The specific equation and method for solving fluid flow will depend on the characteristics of the system, such as the type of fluid and the boundary conditions. In general, the Navier-Stokes equation can be solved using numerical methods or analytical techniques such as dimensional analysis.

3) Can fluid flow equations be applied to all types of fluids?

No, the equations used to describe fluid flow may vary depending on the type of fluid. For example, the Navier-Stokes equation may need to be modified for non-Newtonian fluids or for fluids with high levels of turbulence.

4) What are the limitations of fluid flow equations?

Fluid flow equations are based on certain assumptions and simplifications, which may not accurately reflect real-world situations. Additionally, these equations may not be applicable in extreme conditions such as high velocities or complex geometry.

5) Are there alternative equations to the Navier-Stokes equation for fluid flow?

Yes, there are alternative equations such as the Euler equations, which are commonly used for inviscid flows, or the Reynolds-averaged Navier-Stokes equations, which take into account turbulence effects. The choice of equation will depend on the specific application and characteristics of the fluid flow.

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